GRE Subject Test: Biology : Understanding Digestive Functions

Study concepts, example questions & explanations for GRE Subject Test: Biology

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Example Questions

Example Question #1 : Understanding Digestive Functions

-amylase, found in saliva, plays a role in the digestion of what compounds?

Possible Answers:

Fats

Carbohydrates

Proteins

All of these will be digested by -amylase

Amino Acids

Correct answer:

Carbohydrates

Explanation:

The correct answer is carbohydrates.

Salivary amylase can only digest carbohydrates. Proteases further along in the digestive pathway breakdown proteins, while lipases digest fats. Amino acids are the product of digested proteins.

Example Question #2 : Understanding Digestive Functions

Which of the following macromolecules is broken down by pepsin in the stomach?

Possible Answers:

Lipids

Proteins

Nucleic acids

Carbohydrates

Correct answer:

Proteins

Explanation:

Pepsinogen is released by chief cells into the stomach lumen. In the presence of hydrochloric acid (secreted by parietal cells), this inactive enzyme will be cleaved, creating pepsin. Pepsin is a protease responsible for breaking down proteins that enter the stomach.

Carbohydrates are digested by amylase enzymes, lipids are digested by lipases, and nucleic acids are digested by nucleases.

Example Question #3 : Understanding Digestive Functions

Which organ is responsible for creating bile?

Possible Answers:

Liver

Pancreas

Gall bladder

Stomach

Correct answer:

Liver

Explanation:

Bile is a salt solution used to emulsify fats in the small intestine in order to facilitate absorption. It is created by the liver, but stored in the gall bladder. During digestion, the bile is released from the gall bladder into the duodenum.

The stomach is mainly responsible for mechanical digestion, caused by smooth muscle contractions, and a small amount of protease function. The pancreas secretes a number of digestive enzymes into the duodenum to facilitate digestion of macromolecules. Neither organ is involved in the production of bile.

Example Question #4 : Understanding Digestive Functions

Which is a correct association for cell type and products in the islets of Langerhans?

Possible Answers:

 cells secrete insulin

 cells secrete glucagon

 cells secrete glucagon

 cells secrete insulin

 cells secrete somatostatin

Correct answer:

 cells secrete glucagon

Explanation:

The islets of Langerhans contain the endocrine pancreatic cells. 3 cell types within are the , and  cells.  cells secrete glucagon,  cells secrete insulin, and  cells secrete somatostatin.

Example Question #5 : Understanding Digestive Functions

A patient presents to the hospital with the complaint of pain in his abdomen. Imaging reveals ulcers in his upper small intestine. Further tests reveal that the ulcers are caused by acid entering the small intestine not being properly neutralized.

What organ in the digestive system is malfunctioning, causing these acidic secretions to harm the small intestine?

Possible Answers:

Stomach

Pancreas

Liver

Gall bladder

Correct answer:

Pancreas

Explanation:

Answering this question requires you to know which organ assists in neutralizing acidic chyme once it enters the small intestine. This is the responsibility of the pancreas, which secretes bicarbonate ions. This helps raise the pH of the chyme in the small intestine, and prevents damage.

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